An Nd: YAG laser is a solid-state laser that uses an Nd: YAG (Neodymium-doped Yttrium Aluminum Garnet) crystal rod to produce its light energy. Photons produced by Nd: YAG lasers travel at a wavelength of 1064 nm.

The term “Q-switch” refers to the type of pulse created by the laser. Unlike common laser pointers that create a continuous laser beam, Q-switched lasers create laser beam pulses that last mere billionths of a second. Because the energy from the laser is emitted in such a brief period of time, the energy is concentrated into very powerful pulses.

The powerful, brief pulses from have two key benefits. First, these pulses are powerful enough to shatter tiny fragments of ink or pigmentation, stimulate collagen production, or kill fungus. Not all aesthetic lasers have sufficient power for these applications, which is why Q-switched lasers are prized for their efficacy.

Second, because the energy is in the skin for mere nanoseconds, the surrounding tissue is not harmed. Only the ink is heated up and shattered, while the surrounding tissue stays unaffected. The briefness of the pulse is what allows these lasers to remove tattoos (or excess melanin, or kill fungus) without unwanted side effects.